I can afford $100 (mostly... with a family in tow and none of my games selling well it's not exactly easy, but I CAN afford). Problem is, GD is no longer $100. There is no longer a hobbyist license at all, and, based on what the pro license fees were before, even if they were half now (and I believe it's actually more), I couldn't afford it (and certainly couldn't justify it based on my past, uhh, "success").
So, PF is all that's really left (which is good because PF is very good). But, to have another option is better because choice is always better. If the cost of this library was on par with what GD was, it would be an option for me, and I wouldn't have to consider law school to get a better job to pay for something else
...and so I said to Mr. Gates: "$640 billion should be enough for anyone!"